Does quitting smoking really make you gain 10 pounds?

If you're also pondering a New Year's resolution to lose weight, it might
be tough to give up cigarettes if you fear you'll pack on some pounds because
of it.

University of Michigan researcher Dan Eisenberg is beginning a study to look
at the real cause and effect between quitting smoking and gaining weight.

Eisenberg, assistant professor of health management and policy at the U-M
School of Public Health, isn't ruling out a connection between weight and smoking.
Smoking works as an appetite suppressant, and there is significant literature
showing a relationship between quitting smoking and gaining weight.

"There hasn't been a completely valid estimate of what the connection
is," Eisenberg said. "I am trying to find out the true size of the
causal relationship is."

Part of the challenge in understanding the relationship is that smokers can
either choose to continue smoking or to quit, creating what's called a selection
bias—people sort themselves into one group or the other, and that could create
some of the effect.

Eisenberg said it is possible that those who quit are more health conscious
or more disciplined, and perhaps because of that, they control their eating
better. The true effect of quitting smoking, physiologically, might be something
more like a gain of 20 pounds—but the quitters rein it in.

On the flip side, because there is a general belief that quitting smoking
causes weight gain, perhaps people who are not worried about gaining weight
are more likely to quit smoking. That might mean quitting smoking should only
cause a gain of five pounds, but since the quitters aren't all that worried,
they pack on 10 or more instead.

Eisenberg hopes to untangle some of the question looking at data from previously
published studies by researchers in which smokers have been randomly assigned
to a smoking cessation program or to a “control group.”

Because the studies randomly choose who gets help quitting, selection bias
is not an issue, Eisenberg said. But even with help, not everyone will quit,
so he will look at differences in the probability of quitting.

Eisenberg received a grant of about $18,000 from the University of Michigan
Tobacco Research Network to help fund his pilot research study.

Eisenberg expects to have some early results from the study by summer 2005.